Method of producing balsa slices



oct, 22, 194e.

D. NEWMARK ETAL METHOD OF 'PRODUCING BALSA SLICJES Filed Jan. 7, 1944 Patented Oct. 22, F1946 OFFICE METHOD OF PRODUCING BALSA SLICES David Newmark and William Kramer,

New York, N. Y.

Application January 7, 1944, Serial No. 517,456

1 Claim. 1

This invention relates to slices of balsa wood, either singly or in plies thereof, the method of their production and the product thereof, produced without waste of balsa material; also that the product may present smooth, satinlike surfaces capable of having imposed thereon printed or otherwise delineated designs as guides in cutting out toy or model configurations.

The usual method of producing balsa slices or veneers is by sawing them from a block of that material, but this results in considerable wastage due to the thickness of the Saw and the relatively large amount of wood that is removed in the form of sawdust.

Knife slicing of balsa has been resorted to but so far as is known to applicants the balsa has rst been subjected to a steaming process and the slices are subsequently put through a drying operation. Such slices r Veneers are not employed by us in the present invention.

By the instant method balsa slices and plywood veneers are sheared from a block of dry balsa, the thickness of the blade causing the slices to curl outwardly away from the block, the cut or convex surface of the slice being rough and besides having developed in the slicing operation into a series of lengthwise interstices or crevices at the convex side.

It is more economical to slice the balsa in a dry state, but the consequent roughness of the slice surfaces renders the out slice unsuited to the purposes for which it is intended. Therefore the curved slice is passed between rollers to straighten it, then receives a coating of resin, glue or other adhesive, on the convex surface that had developed the crevices, and finally is passed between heated. pressure rollers, having the effect of impregnating the substance of the slice with the adhesive and impartingr thereto smooth, satin-like surfaces upon which desired delineations can be imposed.

In producing balsa plywood by this method two cut slices of dry balsa are opposed at their convex surfaces, straightened in the same manner as with a single slice, given a coating of an adhesive on the inner surface of one or both of the slices and then passed between the hot, pressure rollers as before.

Obviously the balsa plywood may comprise any desired number of slice plies.

Other features and advantages of our invention will hereinafter appear.

In the drawing:

Figure 1 is a perspective view of a block of balsa Wood, showing a, knife in the act of cutting a slice therefrom, and showing the concavo-convex contour assumed by the slice in the cutting operation.

Fig. 2 is a side sectional View showing a curved slice of balsa in its passage between straightening rollers, over an adhesive delivering roller, and between hot, pressure rollers.

Fig. 3 is a section taken on the line 3-3 of Fig.

Fig. 4 is a section taken on the line 4 4 of Fig. 2.

Fig. 5 is a side sectional View, corresponding to Fig. 2, but showing two slices of balsa being formed into plywood by the hot, pressure rollers, and

Fig. 6 is a section on the line 6-6 of Fig. 5.

In said figures let I indicate a rectangular block of balsa wood, showing a knife 2 angularly operating in the act of severing slices 3 therefrom, and showing that in such severing act the slice assumes a concavo-convex contour, as indicated in Fig. 3, the convex side having developed thereon the crevices appearing in said figure. This curved slice is now passed continually and progressively `between the straightening rollers 4, 4, and passes with its creviced side contactingly over a roller 5 `that is journalled at 6 in a bath 1 of contained fluid resin, glue or other suitable adhesive, an upper roller 8 causing the slice to have frictional contact with roller 5 in order that the adhesive may be applied to said creviced side; or the adhesive may be applied to both sides, in which instance a container like that shown at I4 in Fig. 5 may be added to apply the adhesive also on the upper side of slice 3. Thence the slice continues progressively to a series of heated, pressure rollers 9 and in its passage between pairs of these rollers the adhesive becomes impregnated in the slice of balsa whose surfaces through the applied heat and pressure acquire a smooth, satin-like finish that renders the slice suitable for the designated purposes of the invention.

In the example of the invention illustrated in Figs. 5 and 6 two separate slices I 0, II of balsa `are shown with their convex sides in opposition,

each slice being passed between separate pairs of rollers, respectively l2 and I3, to straighten them; thence said slice I I appears as receiving on its creviced side a supply of an adhesive from a container I4, the slice being supported at this point by a roller I5. Thenceforward the slices are respectively guided by pairs of rollers I6, II toward a series of pairsv of heated and pressure rollers I8, and during the passage of these slices between 3. these pairs of rollers the slices are combined into plywood and impregnated with the adhesive.

By the aforesaid method the plywood surfaces acquire the same smooth, satin-like nish as in the instance of the single balsa slices.

While we have designated balsa as the wood to be treated in the manner hereinbefore set forth, other soft woods, such for example as bass, sugar pine, etc., may be included in the same category, provided their characteristics enable them to respond to the treatment and thus acquire the stated smooth, satin-like iinish capable of receiving imposed delineations for the desired purpose.

Variations within the spirit and scope of our invention are equally comprehended by the foregoing disclosure.

We claim:

The method of producing thin, straight, at slices of balsa wood having smooth, satin-like surfaces, for use in the manufacture of toy and model articles, which consists in cutting said slices from a dry block of balsa by verticaI knife action, whereby each slice acquires a concavoconvex contour whereof the convex side has crevices developed therein, and then progressively subjecting each slice, while continually moving, to the following steps: rst passing each slice between rollers to straighten it, then passing each slice with its creviced side over an adhesive gathering roller, and finally passing each slice between heated pressure rollers.

DAVID NEWMARK. WILLIAM KRAMER. 

